/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.widget;

import static android.widget.SuggestionsAdapter.getColumnString;

import com.android.internal.R;

import android.app.SearchManager;
import android.app.SearchableInfo;
import android.content.Context;
import android.content.Intent;
import android.content.res.TypedArray;
import android.database.Cursor;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.text.Editable;
import android.text.TextUtils;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView.OnEditorActionListener;

import java.util.WeakHashMap;

/**
 * Provides the user interface elements for the user to enter a search query and submit a
 * request to a search provider. Shows a list of query suggestions or results, if
 * available and allows the user to pick a suggestion or result to launch into.
 */
public class SearchView extends LinearLayout {

    private static final boolean DBG = false;
    private static final String LOG_TAG = "SearchView";

    private OnQueryChangeListener mOnQueryChangeListener;
    private OnCloseListener mOnCloseListener;

    private boolean mIconifiedByDefault;
    private boolean mIconified;
    private CursorAdapter mSuggestionsAdapter;
    private View mSearchButton;
    private View mSubmitButton;
    private View mCloseButton;
    private View mSearchEditFrame;
    private AutoCompleteTextView mQueryTextView;
    private boolean mSubmitButtonEnabled;
    private CharSequence mQueryHint;
    private boolean mQueryRefinement;

    private SearchableInfo mSearchable;

    // A weak map of drawables we've gotten from other packages, so we don't load them
    // more than once.
    private final WeakHashMap<String, Drawable.ConstantState> mOutsideDrawablesCache =
            new WeakHashMap<String, Drawable.ConstantState>();

    /**
     * Callbacks for changes to the query text.
     */
    public interface OnQueryChangeListener {

        /**
         * Called when the user submits the query. This could be due to a key press on the
         * keyboard or due to pressing a submit button.
         * The listener can override the standard behavior by returning true
         * to indicate that it has handled the submit request. Otherwise return false to
         * let the SearchView handle the submission by launching any associated intent.
         *
         * @param query the query text that is to be submitted
         *
         * @return true if the query has been handled by the listener, false to let the
         * SearchView perform the default action.
         */
        boolean onSubmitQuery(String query);

        /**
         * Called when the query text is changed by the user.
         *
         * @param newText the new content of the query text field.
         *
         * @return false if the SearchView should perform the default action of showing any
         * suggestions if available, true if the action was handled by the listener.
         */
        boolean onQueryTextChanged(String newText);
    }

    public interface OnCloseListener {

        /**
         * The user is attempting to close the SearchView.
         *
         * @return true if the listener wants to override the default behavior of clearing the
         * text field and dismissing it, false otherwise.
         */
        boolean onClose();
    }

    public SearchView(Context context) {
        this(context, null);
    }

    public SearchView(Context context, AttributeSet attrs) {
        super(context, attrs);

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.search_view, this, true);

        mSearchButton = findViewById(R.id.search_button);
        mQueryTextView = (AutoCompleteTextView) findViewById(R.id.search_src_text);
        mSearchEditFrame = findViewById(R.id.search_edit_frame);
        mSubmitButton = findViewById(R.id.search_go_btn);
        mCloseButton = findViewById(R.id.search_close_btn);

        mSearchButton.setOnClickListener(mOnClickListener);
        mCloseButton.setOnClickListener(mOnClickListener);
        mSubmitButton.setOnClickListener(mOnClickListener);
        mQueryTextView.addTextChangedListener(mTextWatcher);
        mQueryTextView.setOnEditorActionListener(mOnEditorActionListener);
        mQueryTextView.setOnItemClickListener(mOnItemClickListener);
        mQueryTextView.setOnItemSelectedListener(mOnItemSelectedListener);

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SearchView, 0, 0);
        setIconifiedByDefault(a.getBoolean(R.styleable.SearchView_iconifiedByDefault, true));
        a.recycle();

        updateViewsVisibility(mIconifiedByDefault);
    }

    /**
     * Sets the SearchableInfo for this SearchView. Properties in the SearchableInfo are used
     * to display labels, hints, suggestions, create intents for launching search results screens
     * and controlling other affordances such as a voice button.
     *
     * @param searchable a SearchableInfo can be retrieved from the SearchManager, for a specific
     * activity or a global search provider.
     */
    public void setSearchableInfo(SearchableInfo searchable) {
        mSearchable = searchable;
        if (mSearchable != null) {
            updateSearchAutoComplete();
        }
        updateViewsVisibility(mIconifiedByDefault);
    }

    /**
     * Sets a listener for user actions within the SearchView.
     *
     * @param listener the listener object that receives callbacks when the user performs
     * actions in the SearchView such as clicking on buttons or typing a query.
     */
    public void setOnQueryChangeListener(OnQueryChangeListener listener) {
        mOnQueryChangeListener = listener;
    }

    /**
     * Sets a listener to inform when the user closes the SearchView.
     *
     * @param listener the listener to call when the user closes the SearchView.
     */
    public void setOnCloseListener(OnCloseListener listener) {
        mOnCloseListener = listener;
    }

    /**
     * Sets a query string in the text field and optionally submits the query as well.
     *
     * @param query the query string. This replaces any query text already present in the
     * text field.
     * @param submit whether to submit the query right now or only update the contents of
     * text field.
     */
    public void setQuery(CharSequence query, boolean submit) {
        mQueryTextView.setText(query);
        // If the query is not empty and submit is requested, submit the query
        if (submit && !TextUtils.isEmpty(query)) {
            onSubmitQuery();
        }
    }

    /**
     * Sets the hint text to display in the query text field. This overrides any hint specified
     * in the SearchableInfo.
     *
     * @param hint the hint text to display
     */
    public void setQueryHint(CharSequence hint) {
        mQueryHint = hint;
        updateQueryHint();
    }

    /**
     * Sets the default or resting state of the search field. If true, a single search icon is
     * shown by default and expands to show the text field and other buttons when pressed. Also,
     * if the default state is iconified, then it collapses to that state when the close button
     * is pressed. Changes to this property will take effect immediately.
     *
     * <p>The default value is false.</p>
     *
     * @param iconified whether the search field should be iconified by default
     */
    public void setIconifiedByDefault(boolean iconified) {
        mIconifiedByDefault = iconified;
        updateViewsVisibility(iconified);
    }

    /**
     * Returns the default iconified state of the search field.
     * @return
     */
    public boolean isIconfiedByDefault() {
        return mIconifiedByDefault;
    }

    /**
     * Iconifies or expands the SearchView. Any query text is cleared when iconified. This is
     * a temporary state and does not override the default iconified state set by
     * {@link #setIconifiedByDefault(boolean)}. If the default state is iconified, then
     * a false here will only be valid until the user closes the field. And if the default
     * state is expanded, then a true here will only clear the text field and not close it.
     *
     * @param iconify a true value will collapse the SearchView to an icon, while a false will
     * expand it.
     */
    public void setIconified(boolean iconify) {
        if (iconify) {
            onCloseClicked();
        } else {
            onSearchClicked();
        }
    }

    /**
     * Returns the current iconified state of the SearchView.
     *
     * @return true if the SearchView is currently iconified, false if the search field is
     * fully visible.
     */
    public boolean isIconified() {
        return mIconified;
    }

    /**
     * Enables showing a submit button when the query is non-empty. In cases where the SearchView
     * is being used to filter the contents of the current activity and doesn't launch a separate
     * results activity, then the submit button should be disabled.
     *
     * @param enabled true to show a submit button for submitting queries, false if a submit
     * button is not required.
     */
    public void setSubmitButtonEnabled(boolean enabled) {
        mSubmitButton.setVisibility(enabled ? VISIBLE : GONE);
        mSubmitButtonEnabled = enabled;
    }

    /**
     * Returns whether the submit button is enabled when necessary or never displayed.
     *
     * @return whether the submit button is enabled automatically when necessary
     */
    public boolean isSubmitButtonEnabled() {
        return mSubmitButtonEnabled;
    }

    /**
     * Specifies if a query refinement button should be displayed alongside each suggestion
     * or if it should depend on the flags set in the individual items retrieved from the
     * suggestions provider. Clicking on the query refinement button will replace the text
     * in the query text field with the text from the suggestion. This flag only takes effect
     * if a SearchableInfo has been specified with {@link #setSearchableInfo(SearchableInfo)}
     * and not when using a custom adapter.
     *
     * @param enable true if all items should have a query refinement button, false if only
     * those items that have a query refinement flag set should have the button.
     *
     * @see SearchManager#SUGGEST_COLUMN_FLAGS
     * @see SearchManager#FLAG_QUERY_REFINEMENT
     */
    public void setQueryRefinementEnabled(boolean enable) {
        mQueryRefinement = enable;
        if (mSuggestionsAdapter instanceof SuggestionsAdapter) {
            ((SuggestionsAdapter) mSuggestionsAdapter).setQueryRefinement(
                    enable ? SuggestionsAdapter.REFINE_ALL : SuggestionsAdapter.REFINE_BY_ENTRY);
        }
    }

    /**
     * Returns whether query refinement is enabled for all items or only specific ones.
     * @return true if enabled for all items, false otherwise.
     */
    public boolean isQueryRefinementEnabled() {
        return mQueryRefinement;
    }

    /**
     * You can set a custom adapter if you wish. Otherwise the default adapter is used to
     * display the suggestions from the suggestions provider associated with the SearchableInfo.
     *
     * @see #setSearchableInfo(SearchableInfo)
     */
    public void setSuggestionsAdapter(CursorAdapter adapter) {
        mSuggestionsAdapter = adapter;

        mQueryTextView.setAdapter(mSuggestionsAdapter);
    }

    /**
     * Returns the adapter used for suggestions, if any.
     * @return the suggestions adapter
     */
    public CursorAdapter getSuggestionsAdapter() {
        return mSuggestionsAdapter;
    }

    private void updateViewsVisibility(final boolean collapsed) {
        mIconified = collapsed;
        // Visibility of views that are visible when collapsed
        final int visCollapsed = collapsed ? VISIBLE : GONE;
        // Visibility of views that are visible when expanded
        final int visExpanded = collapsed ? GONE : VISIBLE;

        mSearchButton.setVisibility(visCollapsed);
        mSubmitButton.setVisibility(mSubmitButtonEnabled ? visExpanded : GONE);
        mSearchEditFrame.setVisibility(visExpanded);

        setImeVisibility(!collapsed);
    }

    private void setImeVisibility(boolean visible) {
        // don't mess with the soft input if we're not iconified by default
        if (mIconifiedByDefault) {
            InputMethodManager imm = (InputMethodManager)
            getContext().getSystemService(Context.INPUT_METHOD_SERVICE);

            // We made sure the IME was displayed, so also make sure it is closed
            // when we go away.
            if (imm != null) {
                if (visible) {
                    imm.showSoftInputUnchecked(0, null);
                } else {
                    imm.hideSoftInputFromWindow(getWindowToken(), 0);
                }
            }
        }
    }

    /**
     * Called by the SuggestionsAdapter
     * @hide
     */
    /* package */void onQueryRefine(CharSequence queryText) {
        setQuery(queryText);
    }

    private final OnClickListener mOnClickListener = new OnClickListener() {

        public void onClick(View v) {
            if (v == mSearchButton) {
                onSearchClicked();
            } else if (v == mCloseButton) {
                onCloseClicked();
            } else if (v == mSubmitButton) {
                onSubmitQuery();
            }
        }
    };

    /**
     * Handles the key down event for dealing with action keys.
     *
     * @param keyCode This is the keycode of the typed key, and is the same value as
     *        found in the KeyEvent parameter.
     * @param event The complete event record for the typed key
     *
     * @return true if the event was handled here, or false if not.
     */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (mSearchable == null) {
            return false;
        }

        // if it's an action specified by the searchable activity, launch the
        // entered query with the action key
        SearchableInfo.ActionKeyInfo actionKey = mSearchable.findActionKey(keyCode);
        if ((actionKey != null) && (actionKey.getQueryActionMsg() != null)) {
            launchQuerySearch(keyCode, actionKey.getQueryActionMsg(), mQueryTextView.getText()
                    .toString());
            return true;
        }

        return super.onKeyDown(keyCode, event);
    }

    private void updateQueryHint() {
        if (mQueryHint != null) {
            mQueryTextView.setHint(mQueryHint);
        } else if (mSearchable != null) {
            CharSequence hint = null;
            int hintId = mSearchable.getHintId();
            if (hintId != 0) {
                hint = getContext().getString(hintId);
            }
            if (hint != null) {
                mQueryTextView.setHint(hint);
            }
        }
    }

    /**
     * Updates the auto-complete text view.
     */
    private void updateSearchAutoComplete() {
        // close any existing suggestions adapter
        //closeSuggestionsAdapter();

        mQueryTextView.setDropDownAnimationStyle(0); // no animation

        // attach the suggestions adapter, if suggestions are available
        // The existence of a suggestions authority is the proxy for "suggestions available here"
        if (mSearchable.getSuggestAuthority() != null) {
            mSuggestionsAdapter = new SuggestionsAdapter(getContext(),
                    this, mSearchable, mOutsideDrawablesCache);
            mQueryTextView.setAdapter(mSuggestionsAdapter);
            ((SuggestionsAdapter) mSuggestionsAdapter).setQueryRefinement(
                    mQueryRefinement ? SuggestionsAdapter.REFINE_ALL
                    : SuggestionsAdapter.REFINE_BY_ENTRY);
        }
    }

    private final OnEditorActionListener mOnEditorActionListener = new OnEditorActionListener() {

        /**
         * Called when the input method default action key is pressed.
         */
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            onSubmitQuery();
            return true;
        }
    };

    private void onTextChanged(CharSequence newText) {
        CharSequence text = mQueryTextView.getText();
        boolean hasText = !TextUtils.isEmpty(text);
        if (isSubmitButtonEnabled()) {
            mSubmitButton.setVisibility(hasText ? VISIBLE : GONE);
        }
        if (mOnQueryChangeListener != null)
            mOnQueryChangeListener.onQueryTextChanged(newText.toString());
    }

    private void onSubmitQuery() {
        CharSequence query = mQueryTextView.getText();
        if (!TextUtils.isEmpty(query)) {
            if (mOnQueryChangeListener == null
                    || !mOnQueryChangeListener.onSubmitQuery(query.toString())) {
                if (mSearchable != null) {
                    launchQuerySearch(KeyEvent.KEYCODE_UNKNOWN, null, query.toString());
                }
            }
        }
    }

    private void onCloseClicked() {
        if (mOnCloseListener == null || !mOnCloseListener.onClose()) {
            mQueryTextView.setText("");
            updateViewsVisibility(mIconifiedByDefault);
        }
    }

    private void onSearchClicked() {
        mQueryTextView.requestFocus();
        updateViewsVisibility(false);
    }

    private final OnItemClickListener mOnItemClickListener = new OnItemClickListener() {

        /**
         * Implements OnItemClickListener
         */
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (DBG)
                Log.d(LOG_TAG, "onItemClick() position " + position);
            launchSuggestion(position, KeyEvent.KEYCODE_UNKNOWN, null);
        }
    };

    private final OnItemSelectedListener mOnItemSelectedListener = new OnItemSelectedListener() {

        /**
         * Implements OnItemSelectedListener
         */
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            if (DBG)
                Log.d(LOG_TAG, "onItemSelected() position " + position);
            // A suggestion has been selected, rewrite the query if possible,
            // otherwise the restore the original query.
            rewriteQueryFromSuggestion(position);
        }

        /**
         * Implements OnItemSelectedListener
         */
        public void onNothingSelected(AdapterView<?> parent) {
            if (DBG)
                Log.d(LOG_TAG, "onNothingSelected()");
        }
    };

    /**
     * Query rewriting.
     */
    private void rewriteQueryFromSuggestion(int position) {
        CharSequence oldQuery = mQueryTextView.getText();
        Cursor c = mSuggestionsAdapter.getCursor();
        if (c == null) {
            return;
        }
        if (c.moveToPosition(position)) {
            // Get the new query from the suggestion.
            CharSequence newQuery = mSuggestionsAdapter.convertToString(c);
            if (newQuery != null) {
                // The suggestion rewrites the query.
                // Update the text field, without getting new suggestions.
                setQuery(newQuery);
            } else {
                // The suggestion does not rewrite the query, restore the user's query.
                setQuery(oldQuery);
            }
        } else {
            // We got a bad position, restore the user's query.
            setQuery(oldQuery);
        }
    }

    /**
     * Launches an intent based on a suggestion.
     *
     * @param position The index of the suggestion to create the intent from.
     * @param actionKey The key code of the action key that was pressed,
     *        or {@link KeyEvent#KEYCODE_UNKNOWN} if none.
     * @param actionMsg The message for the action key that was pressed,
     *        or <code>null</code> if none.
     * @return true if a successful launch, false if could not (e.g. bad position).
     */
    private boolean launchSuggestion(int position, int actionKey, String actionMsg) {
        Cursor c = mSuggestionsAdapter.getCursor();
        if ((c != null) && c.moveToPosition(position)) {

            Intent intent = createIntentFromSuggestion(c, actionKey, actionMsg);

            // launch the intent
            launchIntent(intent);

            return true;
        }
        return false;
    }

    /**
     * Launches an intent, including any special intent handling.
     */
    private void launchIntent(Intent intent) {
        if (intent == null) {
            return;
        }
        try {
            // If the intent was created from a suggestion, it will always have an explicit
            // component here.
            getContext().startActivity(intent);
        } catch (RuntimeException ex) {
            Log.e(LOG_TAG, "Failed launch activity: " + intent, ex);
        }
    }

    /**
     * Sets the text in the query box, without updating the suggestions.
     */
    private void setQuery(CharSequence query) {
        mQueryTextView.setText(query, true);
        // Move the cursor to the end
        mQueryTextView.setSelection(TextUtils.isEmpty(query) ? 0 : query.length());
    }

    private void launchQuerySearch(int actionKey, String actionMsg, String query) {
        String action = Intent.ACTION_SEARCH;
        Intent intent = createIntent(action, null, null, query, actionKey, actionMsg);
        getContext().startActivity(intent);
    }

    /**
     * Constructs an intent from the given information and the search dialog state.
     *
     * @param action Intent action.
     * @param data Intent data, or <code>null</code>.
     * @param extraData Data for {@link SearchManager#EXTRA_DATA_KEY} or <code>null</code>.
     * @param query Intent query, or <code>null</code>.
     * @param actionKey The key code of the action key that was pressed,
     *        or {@link KeyEvent#KEYCODE_UNKNOWN} if none.
     * @param actionMsg The message for the action key that was pressed,
     *        or <code>null</code> if none.
     * @param mode The search mode, one of the acceptable values for
     *             {@link SearchManager#SEARCH_MODE}, or {@code null}.
     * @return The intent.
     */
    private Intent createIntent(String action, Uri data, String extraData, String query,
            int actionKey, String actionMsg) {
        // Now build the Intent
        Intent intent = new Intent(action);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        // We need CLEAR_TOP to avoid reusing an old task that has other activities
        // on top of the one we want. We don't want to do this in in-app search though,
        // as it can be destructive to the activity stack.
        if (data != null) {
            intent.setData(data);
        }
        intent.putExtra(SearchManager.USER_QUERY, query);
        if (query != null) {
            intent.putExtra(SearchManager.QUERY, query);
        }
        if (extraData != null) {
            intent.putExtra(SearchManager.EXTRA_DATA_KEY, extraData);
        }
        if (actionKey != KeyEvent.KEYCODE_UNKNOWN) {
            intent.putExtra(SearchManager.ACTION_KEY, actionKey);
            intent.putExtra(SearchManager.ACTION_MSG, actionMsg);
        }
        intent.setComponent(mSearchable.getSearchActivity());
        return intent;
    }

    /**
     * When a particular suggestion has been selected, perform the various lookups required
     * to use the suggestion.  This includes checking the cursor for suggestion-specific data,
     * and/or falling back to the XML for defaults;  It also creates REST style Uri data when
     * the suggestion includes a data id.
     *
     * @param c The suggestions cursor, moved to the row of the user's selection
     * @param actionKey The key code of the action key that was pressed,
     *        or {@link KeyEvent#KEYCODE_UNKNOWN} if none.
     * @param actionMsg The message for the action key that was pressed,
     *        or <code>null</code> if none.
     * @return An intent for the suggestion at the cursor's position.
     */
    private Intent createIntentFromSuggestion(Cursor c, int actionKey, String actionMsg) {
        try {
            // use specific action if supplied, or default action if supplied, or fixed default
            String action = getColumnString(c, SearchManager.SUGGEST_COLUMN_INTENT_ACTION);

            if (action == null) {
                action = mSearchable.getSuggestIntentAction();
            }
            if (action == null) {
                action = Intent.ACTION_SEARCH;
            }

            // use specific data if supplied, or default data if supplied
            String data = getColumnString(c, SearchManager.SUGGEST_COLUMN_INTENT_DATA);
            if (data == null) {
                data = mSearchable.getSuggestIntentData();
            }
            // then, if an ID was provided, append it.
            if (data != null) {
                String id = getColumnString(c, SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID);
                if (id != null) {
                    data = data + "/" + Uri.encode(id);
                }
            }
            Uri dataUri = (data == null) ? null : Uri.parse(data);

            String query = getColumnString(c, SearchManager.SUGGEST_COLUMN_QUERY);
            String extraData = getColumnString(c, SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA);

            return createIntent(action, dataUri, extraData, query, actionKey, actionMsg);
        } catch (RuntimeException e ) {
            int rowNum;
            try {                       // be really paranoid now
                rowNum = c.getPosition();
            } catch (RuntimeException e2 ) {
                rowNum = -1;
            }
            Log.w(LOG_TAG, "Search Suggestions cursor at row " + rowNum +
                            " returned exception" + e.toString());
            return null;
        }
    }

    /**
     * Callback to watch the text field for empty/non-empty
     */
    private TextWatcher mTextWatcher = new TextWatcher() {

        public void beforeTextChanged(CharSequence s, int start, int before, int after) { }

        public void onTextChanged(CharSequence s, int start,
                int before, int after) {
            SearchView.this.onTextChanged(s);
        }

        public void afterTextChanged(Editable s) {
        }
    };

    /*
     * Avoid getting focus when searching for something to focus on.
     * The user will have to touch the text view to get focus.
     */
    protected boolean onRequestFocusInDescendants(int direction,
            Rect previouslyFocusedRect) {
        return false;
    }
 }